Coal briquet and process of forming the same.



UNITED STATES PATENT OFFICE.

WARREN WILFORD LANGDON, OF IWJ LLLA WALLA, WASHIITGTONQ- ASSIGNOR TOBAKER 8c BAKER, OF WALLA WALLA, WAS HINGTON, A CORPORATION OF WASHINGTON.

COAL BRIQUET AND BROC ESS OF FORMING- THE SAME.

No Drawing.

To all whom it may concern:

Be it known that I, W'ARREN WI'LFonn LANGDON, a citizen of the UnitedStates, and a resident of \Valla Valla, in the county of \Valla \Vallaand State of \Vashington, have invented certain new and usefulImprovements in Coal Briquets and Processes of Forming the Same, ofwhich the following is a specification.

This invention relates to fuel briquets, and has for an object toprovide a novel briquet as well as an improved process of producing thesame, and the invention consists in the process and in the briquet asmore fully described and claimed hereinafter.

The object of the invention is to produce a briquet which will hold itsshape and re-' main solid when subjectedto a high temperature, so thatit will not disintegrate and fall to pieces when burning; will retainits shape and remain solid and unimpaired when exposed to the elements,stored in wet.

places, or otherwise subjected to'moisture; and will be sutlicientlyhard and infrangible to prevent it from readily breaking up or chippingoff when handled.

It has been found, through a long series of experiments, that briquetsmade with pitch alone as a binder have a tendency to fall topieces whileburning by reasonof the thus made with a paste binder alone, disin-"tegrate or deteriorate when exposed to the elements or otherwisesubjected to moisture.

.It becomes therefore important .to provide a method of producing abriquet and a briquet which will embody efiiciently the merits of bothforms of binder, and in doing this, it has been found necessary todevise a method whereby the two binders may be utilized in an efficientmanner.

- Specification of Letters Patent,

It has been found in all. cases where pitch is used for a binder forbriquets, that it is necessary, in order to secure the roperincorporation of the pitch with t'e coal so .that it will act as anefiicient binder, that the coal at the time of applyin the pitch shallnot contain more than 3% omoisture. If a greater amount of moisture ispresent, itwill prevent the pitch from adhering to the coal particles. Agreater amount of moisture than 3% in the coal will also preventpetroleum or other oil from adhering to the coal particles. 4

In the course of the experiments, it has de veloped that inferiorresults are secured if Patented Jan. 16, 1912. I Application filedJanuary 12, 19 1 1. Serial No. 602,349.

the paste is added to the finely divided coal 1 prior to theincorporation therewith of the pitch, as the moisture'in the paste insuch instance prevents the pitch from readily combining with the finelydivided'coal in such manner as to secure the best results, as it willprevent the pitch from adhering intimately to the coal particles, andthe moisture in the paste will also prevent the pitch from intimatelyadhering to the paste, the result being that the pitch is allowed to actneither as an efficient binder nor as a water-proofing for the coal orfor the paste or for the bri'quet as a whole; and it is found thatbriquets made according to such plan, that is to say, wherein the pasteis associated with the coal prior 'to the mixing therewith andincorporation therewith of the pitch, disintegrate and fall to pieceswhen exposed to moisture.

I In some cases petroleum has beenutilized and applied to the coal priorto the mixing therewith of the paste, but in such cases the "moisture ofthe paste prevents the petroleum from properly forming a water-proofingfor the paste itself, and so allows the paste to soften when the briquetis exposed to moisture. In such case the petroleum will also evaporate,run off, and otherwise wastefrom the surface of the briquet, leaving thesurface subject to disintegration by moisture.

The petroleum so applied has been used and 4 acts, in sofar as it hasanyefficiency, solely as awater-proofin and does not form a binder for thebriquet. It is, therefore, of

service only to the extent of its eliiciency as a water-proofing.

' are not sufficiently strong because the flour when thus used does nothave sufficient binding power, as it should -be boiled and applied whilemoist in order to secure the 1 greatest efficiency.

By my invention, I seek to secure the de-.

' sired results and to avoid the objections hereinbefore referred to,and in carrying out my process I employ in connect on with finelydivided coal, (in such term I would include coal slack, coal dust, coalpulverized practically to a powder, or coal in other finely dividedforms), pitch in a pulverized form, and a paste, .in the manner morefully described hereinafter. In the use of the term pitch I include coaltar,in forms that are solid at ordinary temperatures, water gas pitch,rosin, asphaltum,and any other solid resinous or bituminous substance;

It has been found most practicable to use the pitch in pulverized form.It may, however, be used in melted or semi-fluid form or in any othershape in which it is possible to mix it thoroughly with finely dividedcoal. The paste is preferablya flour paste prepared in the'ordinarymanner commonly used by paper hangers and may be regarded as an ordinarypaper hangers paste. However, any glutinous or starch paste may be used;In making said paste, I may add thereto a strong alkali, such asordinary lye.

or potash, for the purpose of preserving the paste and preventlng itfrommlldewmg or moldlng. I may also use an oil, preferably crude petroleum,in making my briquet, 1n

the manner which I will now describe.

The proportions of the different elements may be varied, but it will befound practicable to use proportions substantially as follows. Thus whenpetroleum is used, I take, by weight, 3% of petroleum, 9% of pitch, 93%of finely divided coal, and 2% of paste. \Vhen petroleum is omitted, asit may be in some instances, I will use 3% of pitch, 2%

of paste, and 95% of finely divided coal.

In mixing the different elements, the coal in finely divided form. isfirst dried so as to contain in no case more than 3% of moisture, thenthe petroleum is added to the finely divided coal and is mixed so as ina measure to soak into or satin-ate the different parti clesof the coal.The pitch, in pulverized form,.will then be added and thoroughly mixedwith the saturated coal. pitch in melted form be used, the coal duringthe addition and mixing of the pitch therewith will have to be.kept ofsufficient temperature to keep the pitch in melted form. It may be saidthat the petroleum is useful'because it incrcasesthe combustibility ofthe product, also limits the absorbing ower of the coal so that it'willtake up less of the pitch, and in localities where the pe- Should.

mixed therewith, so that the mass will be bound together by boththe-pitch and the paste and the pitch will operate as a waterproofingenvelop for the paste; The briquets are then produced by pressure insuitable molds while the mixture is still of such temperature that thepitch therein is in melted form, and it is preferred to heat these moldsin order to secure a glazing or similar finish on the surface of the'briquets. This glazing closes the pores and interstices which wouldotherwise appear on the surface of the briquet, thus making thebriquetimpervious to moisture, and the heat of the dies or molds willoperate first to drive off the moisture of theimmediate surface andthereby allow the pitch on the surface to .become intimatelyincorporated with the paste, thereby, upon cooling, forming awaterproofing for the paste, the pitch also spreading under influence ofthe heated dies or molds uniformly-over the surface to form a completecover or envelop.

It may be stated that the use of the heated die operates to cook,preserve and cure the paste on and adjacent to the surface of thebriquet, thereby preventing the growth of mold, mildew or other funguswhen the briquet is stored for a long period in' damp places.

The briquet produced by the described process differs from the ordinarybriquet in that it consists of finely divided coal in which pitch isincorporated in such manner that the' particles of the coal areenveloped and bound together by the pitch and the paste also unites thesaid pitch-enveloped particles. Thus it will be seen that the pitch inaddition to enveloping the coal particles forms a binder for the entiremass, and the paste also forms a binder for the entire mass, so that thetwo binders eoiiperate in securing a stable-briquet which will'beresistant, by reason of the pitch, from disintegration by moisture, andwill also be resistant, by reason of the paste, from disintegrationunder the influence of heat.

It should be understood that the finely divided coal must be dried priorto the addition of the oil and the pitch so that the coal at the time ofthe-addition of the oil and pitch will contain less than 3% of moisture.The reason for this is that a greater amount tides, and thereforethe ofmoisture in the coal will prevent the oil and the pitch from adheringtothe coal parpitch will not, in such case, act as a binder between thecoal particles.-

.In the mining of coal a considerable portion of the roduct is alwayspulverized.

the fine stuff (below what is called pea coal) is waste and a loss,unless it can be boun together in such a way as to become an artificiallump coal, that is to say, unless it is made into briquets. Now, for abriquet to be a practical commodity, it is necessary that it be hardenough to stand, without breaking. or crumbling, such-handling as coalis ordinarly subjected to in being shipped, hauled and delivered to theconsumer. It must also be unaffected by moisture, so that there will beno disintegration, softening, or erosion of the briquet when it isexposed to the elements or when it is storedin damp basements or evenunder water. Furthermore, it is most essential that the briquetshouldhold its shape. and not disintegrate when it is subjected to the heat ofa furnace and is being consumed in the fire; for, withcoal.

out this quality, the time, labor, and expense of manufacture were to nopurpose, and the dust had better been fed directly to the fire withouthaving-gone through an intermediate briquet state.

It has heretofore been the common experience of those engaged in thebriqueting of coal that the only practicable and successful binder forthe manufacture of briquets was" pitch. Now, it is found by all that abriquet in which pitch alone is the binding agent will necessarilydisintegrate in the fire, on account of the fact that the heat of thefire melts the pitch and thereby leaves the briquet without-a binder,for melted pitch has practically no binding qualities; and the briquetreturns to its original form of finely divided coal. In such case noadvantage has been gained in briqueting the It'has, therefore,been'found absolutely necessary to utilize some other agent inconjunction with the pitch which will act as a binder when the pitchbecomes melted and which will hold the briquet' together until it isconsumed. In the past, the means of accomplishing this result adopted bypractically all plants in commercially successful' operation has been toconfine 'the 'briqueting operations to coking coal-that is to say, tobituminous coal. Such coal is briqueted with a pitch of sufficientlyhigh melting point that as soon as sufficient heat is applied to meltthe pitch, it at the same fuel, but with atime, by reason of thepeculiar qualities of bituminous coal, caus'es'the particles of coal toadhere together, forming one soli body,-in other words, the'coal of thehuquet begins to coke. On account of this very quality of bituminouscoal which causes it to coke under heat, finely divided bituminous coalcan be successfully handled and used as fuel without briqueting. For,whereas pulverized, non-coking coal is forced through the smokestackbythe draft, un-

con'sumed, or is dropped through the grates, bituminous coal beginsimmediately to coke on being thrown into the furnace, and 1s therebyheld and consumed in the fire. 'The. result is that all the coal minedfrom bi-' tuminous veins can. be utilized as fuel, whereas at every mineof non-coking coal there is an enormous pile of pulverized coal which isgenerally waste, as it cannot be held in a furnace so as to utilize itsheat units, burned in thedump pile in order to get it out ofthe way.Furthermore, the majority of lignites have a greater tendency than othercoals to slake in the air soon after being mined, making it necessaryfor the product of the mine to .be handled at once, and at best there isan enormous waste from siaking. i

From the foregoing it will be seen thatthe most profitable and usefulfield for briqueting should be with lignites, provided an economicaLbinder were used which could hold the briquet together-in the fire. Thatsuch a binder has not in the past been found, is attested by the factthat prominent engineers who are interested in and who contract for thebuilding of briqueting plants assert that they are unable to make acommercially successful lignite briquet. One method which has beenemployed to overcome these ditliculties has been to mix with thenon-coking coal which it is desired to briquet a little bituminous coal,the mixture then being briqueted with a pitch binder. I understand thishas met with some success in the briqueting of anthracite slack,However, it is often diflicult to obtain bituminous coal in lignitefields, and I know of no case where this method has been successfullyemployed in the briqueting of lignite. In some cases clay has been addedto non-coking coal, and in others lime and other like substances, theidea being to find some substance that will hold the briquet togetherwhen the heat has melted the pitch binder. One great objection to theaddition of such substances is that they materially increasethefpercentage of ash and thereby decrease the desirability of theproduct. In so far as it is possible, nothing considered as so much 5and it is often ineombustible should be added to the coal;

or other starch, has

been tried as 'a binder pitch; but, so far, starch binders have not beenfound successfuhon account of the difficulty in securing, when such abinder'is used, a briquet which is sufficiently hard, and one which willnot soften and dissolve when subjected: to moisture. Then there havebeen numerous attempts ,to use a comb1na-' tion of pitch and starchpaste, the object being to secure abinder or combination of binderswhich will resist both moisture and heat. So far as I have been able toascertain, none of these attempts have'been successful for the reasonthat the wrong system and order of applying the binders were used.

Like oil, pitch, when melted, will not mix with water, nor will themelted pitch adhere to any wet surface. In my experimenting with boththe lignite and bituminous coals of the Puget Sound country, I havefound that, in order tosecure astrong adhesion of the pitch to the coal,it is necessary to re,-.

sufficient temperature to melt the pitch, and,

while still of this temperature, delivered the mass to the press andmolded it into bri uets. These briquets were harder on cue ing thannewly made paste-binder briquets. However, I found that they were farfrom water-proof. In fact, after they had cooled and dried so that theywere hard enough to sustain the weight. of an average man, they softenedand went entirely to pieces in the course of half an hour on beingplaced in water at anordinary temperature. ()n the other hand, a briquetmade from the same coal using only pitch as a binder, using the samekind of pitch and the same proportion, 80 pounds. to the ton, was foundto be hard and unaii'ected by immersion in water.

\Vhat happened in the case of the briquet made with both paste and pitchas binders. as above described, was this-i \Vhen I put thepaste into thecoal, practically all the.

particles of the coal received a-thin coating of the paste. Now, whenthe pitch was added and melted, the paste was between the coal and thepitch, and prevented the pitch for uniting with-the coal. 150, themoisture of the paste prevented the pitch from mixing with and adheringto the paste. The result was that in large measure the pitch remained aseparate substance,'not adhering to any of the other substances makingup the mass; and, on examining the mass, the small, unattached globulesof pitch could be plainly seenQ Undoubtedly here and there the pitchfound a dry enough surface to adhere to, and by reason of this, thebriquet was stronger than one made with paste alone. When the briquetwas molded and cooled, the globules of pitch hardened, still. withoutadhering to the particles of coal, f,

since the moisture still remained in the paste,

and therefore the pitch acted neither as a binder for the briquet to anypractical extent nor did it act as a-waterprooting for the paste.Therefore, when the briquet was subjected to moisture, the pastedissolved and the briquet disintegrated; In view ofthe thoroughresistance to moisture of the simple pitch'binder briquet made from thesame coal, the speed with which thiscpitchpaste briquet disintegratedwas astonishing.

I then made a briquet'in accordance with the process described inBritish patent to Danvers' No. 897, March 11, 1875 (4A1).

For this I proceeded as follows: I took 500 pounds of dry, finelydivided, ligniteofthe same lot used in the other experiments mentionedabove: 22.5 pounds of pitch; 3/4 of a gallon of coal;tar; and 5/ lpounds'of dry flour; these being the proportions indicated inthespecifications of the Danvers' process. I then melted the pitch in thetar, and when the whole mass became fluid and was brought up totheboiling point and allowed to boil. for a few minutes, I addedtheflour in its dry state and mixed it thoroughly in the boiling mass, sothat it became thoroughly incorporated in the mass, forming a tar-)itclipaste. This hot mixture was then added to the 500 pounds of coal,and was thoroughly mixed therewith in a mixing machine heatedsufficiently to maintain the temperature. Then the mass, while stillhot, was'delivered to and run through the press in the usual manneremployed in making briquets. I also tried experiments varying theprocess by increasing the amount of pitch, and the amount of tar, andalso the amount of flour, and changing the order of application.

In all my experiments with the Danvers process, I had great diilicultyin securing even a tanbriquet from the press, not more than of thenumber coming out whole; whereas, in the case of the briquets made by myimproved process at least 95% of the briquets come out of the presswhole and perfect. I account for this by the .fact that l have found inmy experiments, and it is the experience of others engaged in thebriqucting of coal. that, where as pitch or tar binder is used, it isnecessary to add water to the mass, just. before delivering it to the)rcss. in order to secure 'whole, hard briquets. This is accomplished inmy process by the addition of the water-made paste just before going tothe press. While the addition of water is entirely contrary to thetheory of the Danvers patent, yet, in order to obtain better briquetsfor further experimenting', I made the experiment of adding water to theDanvers mixture just before delivering it to the press, and I therebyobtained much improved briquets, and a-much larger proportion came outwhole.

The .briquets obtained by the Danvers process, upon cooling, were fairlyhard, so that they could be handled without breaking, and had theappearance of fair briquets. Moreover, they were water-proof. However,upon throwing these briquets into a boiler furnace with a moderatelyheavy draft, I discovered that the heat, as they began to burn, causedthe binder to melt, and allowed the briquet to disintegrate and toreturn to the original form of finely divided coal. This was the casewhether the briquets were made by strict adherence to the Danversprocess, or by the addition of water as the mass went to the press, asabove described. very plain. WVhen paste is made by boiling flour orother starch in water and it is used. as-a bond between two solids, itsgreatest binding power is obtained by drying the water out of it,leaving the paste a solid, dry starch uniting the two othersolids. Theliquid constituentof the paste is eliminated. Now, when paste is made byboilin starch in tar instead of water, to secure tie same final bondasthat secured in the case of water-made paste, it would be necessary tofind some meansof driving off the tar-from the mixture so as to leavethe bend a solid starch instead of a plastic mixture of tar or pitch andstarch. Of course, this cannot be done, and it is not intended to bedone, in making a briquet by the Danvers process. On the contrary thepaste obtained by the Danver's process is a tarry, plastic mass,composed of starch, tar, and pitch, so mixed together as to form one,composite substance. Granting that this is so made by the boiling and bythe use of pitch that when cool it becomes a solid, and is such a binderas will make a hard, water-proof briquet, yet, since the hardening ofthe mixture is ac- -complished not by drying or. in any other waydriving ofl any fluid constituent, but simply by reducing thetemperature, therefore, when such a binder is again raised to thetemperature at which it'was originally fluid when mixed with the coal,it will again become fluid; and where such a binder is 'used in makingbriquets, it will necessarilymelt in the fire and allow the briquet toreturn to the form of coal slack. In the case of water-made paste, afterit has hard- The reason for this ismade paste', the fluid constituentispresent all the time, and as soon as the sufficient heat is applied, itimmediately becomes liquid, being brought back to'the exact state it wasin when the ingredients were mixed together. Heat, on the other handdoes not affect the water-made paste until it is consumed. In otherwords, a tar-made paste, or an oil-made paste, or a pitch-made paste,-is merely a composite substance which becomes more or less solid whencold and be comes fluid when hot. Since the flour, tar, and pitchintimately combine, there is no opportunity for the flour, the pitch andthe tar to act as binders independently of each other. Itis onesubstance, whichis water proof, to be sure, but is subject to theinfluence of heat and melts in the fire. It is evident that 'if we couldat one and the same time utilize the qualities of both the simple pitchbinder and of'the simple starch-paste binder, we :would secure a briquetwhich would be capable of resisting the disintegrating influences ofboth heat and moisture; and furthermore, we would be adding no materialwhich would detract from the desirability of the fuel.

We have already noticed that when watermade paste is added to the coalfirst, ,the pitch is'prevented from adhering to thepaste-envelopedparticles, and the pitch is left a separate anduncombined substance. Now, why not combine the dry coal and'the pitchfirst, andfby adding the paste later, leave it the uncombined, separatesubstance? This is the method pursued in the present invention: I firstmix pulverized pitch into the dry, finely divided coal, then heat the.mass, thereby melting the pitch, which at once spreads among the coalparticles and adheres to the surfaces, the mixing continuing at the sametime. I then mix into the mass a water-made paste, which, by reason ofits moisture, is prevented from adhering I to such of the surfacesof'the particles of the coal as are covered with the melted pitch, andalso from mixing in any way with the pitch. It is kept a separate andindepend-' ent substance, except where it comes in contact with thesesurfaces or portions of surfaces which are not thoroughly coated withthe melted pitch; to which surfaces or portions of surfaces it, ofcourse, adheres. So I find in this mass, on examining it, in-

stead of the pitch in small, separate, globules, the wet. paste in smallglobules throughout the mass, heldthere as a separate substance,-uncombined with the pitch. The mass is then delivered to the press andbriqueted. 'As the material comesunder the pressure of the molds,wherever pitch covered'surfaces come together, the paste is crowded out,since its moisture prevents. its

mixing with the pitch, and said pitch-cov- .ered -.su'rfaces becomeunited by the pitch.

The paste is thereby confined. to such portions of the surfaces of the'coal particles as are not pitch-covered and to the interstices betweenthe coal particles. The manner in which the paste fills the intersticesmight be illustrated in this way: Suppose you take a quantity of leadshot and cover the surfaces withmelted pitch. You then put in wet pasteand press the mass together. The pitch. repels the wet paste, and thesurfaces of the shot, wherever they touch one another, become united bythe pitch, While the paste is crowded into the spaces between the pointsof contact.

Returning to the hriquets; as they leave the press, they begin to 00 1,and the pitch at once hardens. As soon as the pitch becomes a solid, itloses itsquality by which it repelled the wet paste; and the paste,which is filling the interstices as an independent substance, at oncetakes hold of the surfaces covered with the now hardened pitch, withwhich it is surrounded, in addition to such surfaces as were not coatedwith pitch and to which it had already adhered. As the paste dries, thebriquetis then firmly bound together both by the pitch and by the paste,

each acting independently of the other. The result is-and I have provedthis conclusively by my experimentsthat I have a briquet which, byreason. of the pitch bindby moisture; and which, at the same time,-

iug the particles of coal together, is hard and water-proof and cannotbe dlsmtegrated cannot be disintegrated by heat when it'is in the firefor the reason that the coal particlesi are also bound together by a drystarch paste, which has bound together both pitch covered surfaces andalso those surfaces which were not thoroughly coated with the pitch.Since this paste is unmixed with the pitch, it is unaffected by themelting of the pitch, and is found not to be dissolved. there by duringthe time the briquet is burning. Probably the greatest binding strengthof the paste when the briquet is hot is between those portions of thecoal surfaces which were not covered by the pitch. At any rate, it isfound sullicient to'hold the briquet to- .gether in the fire under theheaviest draft,

whereas the briquets made by all the other .processes mentioned with thesame coal go to pieces under the same conditions.

It thus appears that the moisture in the paste, instead of having been adetriment, is the very agent needed, and acts, when the proper processis used, so as to-enable one to secure two separate binders. actingindepeudently of each other on the same particles. When the wrong,system 1s used, as

when the paste is put in first, the moisture and this is not sufficientto secure either a hard briquet or one that will resist moisture. Whenmy method is used, the moisture serves to allow both-binders to act asbinders .independently of each other, so that I get the full benefit ofthe combined strength of the two binders when the briquet is handled andstored under ordinary conditions, mak ing it specially hard and tough sothat practically no briquets are broken up in handling; and in additionthe pitch serves to hold the briquet together when subjected to severeexposure to moisture; and further more, after the pitch has becomemelted in the fire, the paste still continues to act as a binder for thebriquet sufliciently strong to hold the-briquet intact under thestrongest draft and until it is completely consumed.

In conclusion I have found by my experiments that the briquets made bymy process, aside from having the combined qualities ofbeing bothwater-proof and free from disintegration in the fire, are harderandtougher and less brittle than the briquets made by the Danversprocess, or than thebriquets made with the simple pitch hinder, orthanthe briquets made with the simple paste hinder, or than briquetsmade with a combination of pitch and paste put together in any other waythan by the process herein described. I have found them practicable tomanufacture, while it is ah 0st impossible to make whole bri'quets bythe, anvers process, using the same press that is so successful with myprocess. Moreover, being able to cut down the required amount of pitchby the addition of a paste binder working in conjunction with the pitch,I secure-a briquet which is much more desirable than a simple pitchbriquet for domestic use on ac count of its being much less smoky andmuch cleaner than the simple pitch briquet, and one which gives noobnoxious smell of pitch, tar, or oil, either when stored or whenburning; and I have a briquet which holds its shape no matter how hotthe fire, how strong 110 the draft, or how rough the treatment.

I claim:

1. The process of producing coal briquets which consists in dryingfinely divided coal so that it containsnot more than of 115 moisture,then mixlng said finely divided coal with an oil, then mixing therewitha pitch, then subjecting the mass to heat 1 whereby to melt the pitchand intimately associate it with the finely divided coal, and -12Osubsequently adding and mixing with the mass :1 water-mixed paste, allsubstantially as described, whereby the pitch will operate whichconsists in drying finely divided coal so that it contains not more than3% of moisture, then mixing said finely divided coal with a pitch, thensubjecting the mass to heat whereby to melt the pitch and intimatelyassociate it with the finely divided coal, and subsequently adding andmixing With the mass a water-mixed paste, all substantially asdescribed, whereby the pitch will operate as a binder in resistance tomoisture, and the paste-will operate as a binder both in conjunctionwith the pitch and also when the pitch has become softened by heat asthe briquet burns, as and for the purposes set forth. 7

a 3 A briquet consisting of finely divided coal With which an oil hasbeen'niixed, pitch incorporated with the coal particles, the latterbeing enveloped and united by the pitch, and Water-mixed paste unitingthe said enveloped particles, all substantially as and for the purposesset forth.

4. A briquet consisting of finely divided coal, pitch incorporated withthe coal particles, the latter being enveloped and united by the pitch,and water-mixed paste uniting the said enveloped particles, allsubstantially as and for the purposes set forth.

5. A briquet consisting'of finely divided coal, pitch incorporated withthe coal particles, the latter being enveloped and united by the pitch,and Water-mixed paste uniting the said enveloped particles, the saidbriquet having the pitch uniformly spread upon its outer surface forminga Water-proof and n'lold-proof glaze, substantially as set forth.

\VARREN WVILFORD LANGDON. lVitnesses H. C. BAKES, EMMA LANGDON.

